Vehicle lift



June 18, 1946. E. B. THOMPSON VEHICLE LIFT Filed Feb. 15, 1945 ELMER BTHoMRs'oN 2 MM 45 m 2 &v m m al 2 4 A 6 M a 4 4 0 x I ll. Iii IP11}. I W 3 6 L 7 Z 6 9 I W LWEI l 6 5 \m 51 w flwmfiwi a 2 0W] 5 5 7 ll f V 2% 5 |11 71 5 ll m Patented June 18,

" vsmorn urr Elmer B. Thompson, Des Moines, Iowa, assignor to Globe Hoist Company, Des Moines, Iowa, a

corporation of Iowa Application February 15, 1945, Serial No. 578,028

6Claims.

This invention relates generally to vehicle hoists and in particular to an automobile lift of semi-hydraulic type.

An object of this invention is to provide an improved vehicle hoist.

Another object of this invention is to provide a semi-hydraulic hoist having a, liquid containing lift pistonoperative in a cylinder, in which a normal level of the liquid within the piston is capable of being visually observed on a gauge member removable through the top of the piston.

A further object of this invention is to provide a vehicle hoist of semi-hydraulic type in which air under pressure is introduced into a lift piston, normally having a body of liquid therein, through an air conduit extended upwardly through the base of the. hoist cylinder and through the bottom of the piston to a position above the normal level of the liquid in the piston, with the piston being movable relative to the air conduit and in liquid sealed engagement therewith.

A feature of this invention is found in the provision of a semi-hydraulic hoist having a cylinder and a, hollow lift piston normally having a body of liquid therein, in which the flow of liquid between the piston and the cylinder is controlled by means located within the piston and including a float piston. An upright projection on the float piston is guidably supported within the lower end of a liquid-level indicating rod, with the upper end of the indicating rod being rotatably supported on a downward projection formed on a plug for sealing an opening in the top of the lift piston. The plug on being loosened constitutes a hand grip for lifting the indicating rod upwardly from the lift piston to provide for the visual observing on the rod of the liquid level in the piston, with a stop portion adjacent the upper end of the float piston projection being engageable with the lower portion of the indicating rod to provide for the removal of the float piston from the lift piston when the rod is raised out of the lift piston.

Further objects, features and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawing in which:

Fig. l. is a vertical sectional view of a vehicle lift of semi-hydraulic type showing the liquid control means and the liquid level indicating means of this invention in assembly relation therein;

Fig. 2 is a plan view of the lift shown in Fig. l;

Fig. 3 is a sectional'view on the line 3-3 in Fig. 1; i Fig. 4 is a sectional view taken on the line Above the top cover I! and within the piston ll is an annular ring It having angularly spaced bolt holes l8 to provide for the securement on the piston of a vehicle supporting structure (not shown). The lower end of the cylinder'lfl is closed by a base member I 1 which is integrally formed with an air passage l8 havin one end go is arranged to a side of the cylinder and at an opposite end 2| open to the bottom of the cylinder at a position substantially coincident with the longitudinal axis of the cylinder.

As clearly shown in Fig. 1 the piston operates in a spaced relation within the cylinder It. This spaced relation is maintained by means includins a guide ring 22 at the lower end of the piston and in bearing engagement with the wall of the cylinder l0. Supported on an annular flange 23 about the upper end of the cylinder I0 is an annular member 24 of a substantially L shape in cross section having one leg portion 26 positioned between the piston II and the wall of the cylinder It in bearing engagement with the piston. The other leg portion 21 is extended radially from the piston I I across the top surface of the flange 23 and against an upwardly extended outer peripheral rim member 28 on the cylinder flange 23.

In order to reduce leakage of oil about the piston and outwardly from the upper end of the cylinder it an oil seal is provided which comprises a clamping member 28 of an annular shape having an undercut recess 3| in its inner peripheral wall andopen to the bottom side thereof, as viewed in Fig. 1. The recess M is of a substantially right angle shape in cross section and 88 away from each other so that one of the side portions is pressed in sealing engagement against the piston ii, and the other side portion against the outer wall of the recess 36.

In the assembly of the oil seal an annular upright projection 35 on the annular member 24 is received within the concave recess 33 and against the piston H to a position with its leg portion 26 between the piston H and cylinder l9, and leg portion 21 supported on the cylinder flange 23 between the piston and the rim 28. The clamp ing member 29 with the annular rubber member 32, and spring 34 assembled within the recess 3| is then slipped over the top of the piston II and is moved downwardly to a position within the rim 29 and with the bottom side against the top surface of the member 24. This engagement of the members 24 and 29 takes place concurrently with the location of the annular projection 35 within the recess 3| and against the spring 34.

To eliminate the passage of any water, dirt or the like on an extended part of the piston Ii into the cylinder ID a piston wiper, indicated generally as 31 is assembled about the piston and on the top of the member 29. The piston oil wiper 31 is clamped against the member 29 by means including an annular. cover plate 38, with the plate 38, and the members 24 and 29 being clamped together with the cylinder flange 23 by angularly spaced bolts 39 extended therethrough. It is seen, therefore, that the annular guide member 24, the piston oil seal, and the piston oil wiper 31 are arranged in that order in a superposed relation at the top of the cylinder l and secured as a unit to the cylinder flange 23 by the bolts 39.

The piston H has a normal body of liquid therein, indicated generally as 4|, extended to a level shown as L. In other Words the piston i is substantially filled with a liquid such as oil when it is in a lowered position. Connected to the opening 2| of the air passage l8 in the cylinder base I1 is an upright pipe member 42 which extends upwardly through the bottom cover plate l3 of the piston I and into the piston to a position above the normal level L of the oil body 4 I. Concentrically arranged about the pipe 42 is a tubular guide member 44 secured at its lower end within an opening 43 in the piston bottom cover l3 and supported at its upper end by angularly spaced brace members 45 welded at their inner ends to the tube 44 and at their outer ends to the inner wall of the piston (Figs. 1 and 3). Within the upper end of the tube 44 is a tubular sleeve or collar 41 in contact engagement with the pipe 42. lower end of the tube 44 and about the pipe 42 is an oil packing or seal 48 adapted to prevent any flow of oil from the piston H to the cylinder l0 through the tube 44.

The flow of oil from the piston into the cylinder In takes place through an oil passage or opening 49 formed in the bottom cover l3 of the piston N (Fig. l) to one side of the tubular guide member 44. The flow of oil through the opening 49 is controlled by a valve unit including a. spherical float piston operatively associated with an upright tube 59 located within the piston II and arranged in a concentric relation about the oil opening 49. The lower end section 52 of the tube 59 constitutes a cylinder for the float piston 5|. Above the cylinder 52 the tube 50 is formed 'with angularly spaced longitudinal slots 53 for admitting oil from the piston H with- Supported within the in the cylinder 52, while the solid portions 54 between the slots 53 serve as guide members for guiding the float piston 5| into and out of the cylinder 52. The upper end of the tubular member 50 terminates in upwardly and outwardly inclined fingers 56 for a purpose to'be later noted.

In the operation of the hoist assume the piston H to be in its lowered position shown in Fig. 1. At this position of the lift piston H the float piston 5| is away from the opening 49 whereby oil is contained within the cylinder l9 below the piston H, and within the space 59 between the piston H and cylinder II], which space 59 is in liquid connection with the piston l l through the opening 49 and openings 9| in the piston well below the cover l3. To lift the piston, and in turn a vehicle supported on the piston, air under pressure is introduced into the piston, from a suitable source, such as a pressure tank or the like (not shown), through a pipe connection Bl connected with the end |9 of the air passage iii in the cylinder base H. The air thus introduced passes upwardly through the pipe 42 and into the piston above the body of oil 4|. With the application of an air pressure on the oil body 4|, oil is forced through the opening 49 in the piston cover member l3 and into the cylinder It.

On the application of an air pressure on the oil body 4|, therefore, the all within the cylinder I0 is placed under a pressure which acts against the under side of the piston cover member l3 to raise the piston. By virtue of the fact that the level L of the 011 body 4| in the piston H is lowered concurrently with a raising of the piston the upper end of the pipe 42 is always above the liquid level in the piston. When this level approaches the top of the valve cylinder 52 the float piston 51 moves within the cylinder 52 so that the pressure of the air within the piston II is applied directly on the top surface of the float piston 5| to force the float piston downwardly within the cylinder 52, This downward movement of the piston 5| forces the oil within the cylinder 52 outwardly through the opening 49 and the piston 5| into seating engagement with the oil passage 49, as shown in dotted lines in Fig. l, to stop a further flow of oil from the piston into the cylinder l0, whereby the piston is stopped against further upward movement.

The upward travel of the piston is limited by the,

engagement of a stop ring 45 on the piston II with the lower edge of the annular member 24.

The stop ring 45 is spaced upwardly from the guide ring 22 a distance such that the piston H is always supported in the cylinder l0 against tilting movement.

It is seen, therefore, that the float piston 5| closes the opening 49 prior to a complete passage of oil out of the piston The operation of the piston II is thus at a predetermined speed controlled entirely by the rate of flow of the oil through the passage 49. As a result any air under pressure within the piston is prevented from entering the cylinder ID, to thereby eliminate any sudden lifting or jumping movement of the pisilzgn II as would occur if air did enter the cylinder The lifting action on the piston II by air is about ten times faster than the action by oil. It is apparent, therefore, that the sudden lifting of the piston by air in the cylinder I0 might result in the shearing or breaking of the bolts 39 by the impact of the stop ring 45 with the member 24.

To assure a proper operation of the hoist at all times it is necessary to have the piston ll filled 5 I/ with oil between predetermined levelsf'f'hus even though an oil'seal is provided between the eviinder l and the piston H, 911 will seep or leak out so as to reduce the volume of the oil body ll. In order to give a quick and accurate visual indication of the level of oil within the piston ii there is provided a flat indicating rod or oil gauge 82 having an annular member 03 secured in an offset relation at its lower end adapted to be loosely received in a centered position within the top of the upright tube 50 (Fig. 1). The float piston 5| has an upright projection or rod 54 which'is slidably movable in a guided relation within the disc 83. A top portion on the rod 64 maintains the rod it against separation from the disc 83.

The oil gauze or rod 62 is formed with a laterally bent portion 81 at its upper end (Figs. 1

' and 4) having an opening 88 therein adapted to loosely receive a screw 69 which is threaded within the bottom side of a plug H. The plug II is threadable within a threaded opening 12 in the piston top cover member l2. Theopening'l! is of said cylinder, means for introducing air under a size to permit passage therethrough of the bent rod portion 61, thedisc 63 and the float piston 5!. It is seen, therefore, that the screw 68 is rotatable within the opening 88 in the rod portion Bl, while retaining the rod 82 in a supported position on the screw head 13.

- To determine the level of oil in the piston 'H the plug H is loosened and then used as a hand grip by which the rod 62 is pulled upwardly through the opening l2. As shown in Fig. 1 the rod has full and low" markings thereon for indicating the level of the oil body 4|. It is apparent, of course, that on raising of the r d 62 the disc 83 is lifted'out of the tubular member 50. However, on lowering of the rod 52 the disc E33 is guided into a centered position within the tubular member 50 by its initial reception within the upwardly and outwardly flared fingers lit at the top of the tubular member 50. With the rod 62 in a lowered position within the piston ii the plug ii is threaded within the opening I2 to again close the top it of the piston ii.

if, for somereason it is necessary to remove the float piston 5|, as for example when the piston El becomes oil logged or the like, this can be readily accomplished by merely removing the plug H and pulling the rod 62 upwardly through the'opening 112. During this upward movement of the rod 62 the disc 83 engages the stop member 66 on the float piston rod 64 whereby the piston I! is raised concurrently with the rod 82. As a result the rod 62 and float piston 5| are removable as a unit through the opening 12. On the return of the float BI and rod 82 within the piston ll both the float and the disc 63 are'guided within the tubular member 50 by the action of the guide fingers 58. s

It is seen, therefore, that. the indicating rod 62 is readily accessible from the top of the piston ii and by virtue of its rotatable connection with the plug ll easily lifted out of the piston H with the plug for a reading of the markings thereon. Further the assembly of the float piston 5| with the rod 62 provides for the removalof the piston El with the rod- 62. The disc member 63, in its centered position within the tubular member 50, constitutes a stop device for limiting the upward movement of the float piston 51 so that the float is always in a position to be guided into the cylinder 52 for movement toward and away from the oil opening 49.

Although the invention has been described with pressure into said lift piston above the level of the liquid therein, means for controlling the flow of liquid through said passage including an upright cylinder positioned on the bottom of said piston about said liquid passage, a float pis-L'm for said upright cylinder movable into and out of a passage closing position, an upright liquid .level indicator within said piston adapted to be raised through an opening in the top of said lift piston, means for normally closing said opening, with the lower end of said indicator being-extended to a position adjacent to said upright cylinder, and means connecting said indicator with said opening closing means, and with said float piston so that said closing means, said indicator, and said float piston are removable as a unit through said opening.

2. In a semi-hydraulic lift including a cylinder with a hollow lift piston therein, with the lift piston and the cylinder having a body of liquid therein, a liquid passage in the bottom of said lift piston open to said cylinder, means for introducing air under pressure into said lift piston above the level of the liquid therein, means for controlling the flow of liquid through said passage including a float means within said lift piston movable into and out of a passage closin position, said lift piston having an opening in the top thereof, means for normally closing said opening, and lost motion means connected between said closing means and said float means to provide for the removal of said float means through said opening on removal of said closing means.

3. In a semi-hydraulic lift including a cylinder with a hollow lift piston therein, with the cylinder and the lift piston having a body of liquid therein, a liquid passage in the bottom of said piston open to said cylinder, means for introducing air under pressure into said lift piston above the level of the liquid therein, means for controlling the flow of liquid through said passage including an upright cylinder within said piston positioned about said liquid passage, a float piston for said upright cylinder movable into and out of a passage closing position, with said lift piston having an opening in the top thereof adapted to receive said float piston therethrough, means for closing said opening, means supported from said closing means and extended within said upright cylinder, with the lower end of said extended means constituting a stop to limit theupward movement of the float piston within said upright cylinder, and lost motion means connecting the lower end of said extended means with said float piston whereby said float piston is removable through said opening on removal of said closing means.

4. In a semi-hydraulic vehicle lift including a cylinder closed at its bottom end, a hollow lift piston associated with said cylinder, with the lift piston and the cylinder containing-a body of liqembodiment thereof, it is.

asoacos said cylinder, an upright air conduit extended.

through the bottom end of said cylinder and 7 through said bottom wall to a position above the liquid level in said lift piston, means for liquid sealing said .air conduit with said bottom wall, means within said lift piston for controlling the flow of liquid through said liquid passage including an upright tubular cylinder concentrically arranged about said liquid passage, 8. float piston operatively associated with said tubular cylinder, means projected upwardly from said tubular cylinder for guiding said float piston into and out of the upper end of said tubular cylinder, an upright guide member on said float piston having a stop portion adjacent its top end, means for indicating a level of the liquid in said lift piston including an indicating member having one end slidably movable on said guide rod and an oppo site end extended to a position adjacent said threaded opening, and a rotatable connection between said plug member and the opposite end of said indicating member, with said indicating member being movable through said threaded opening, on removal of said plug member, and having markings thereon to visually indicate the level of the liquid in said lift piston, said one end of the indicating member being engageable with said stop portion to provide for the joint removal of said indicating member and said float piston from said lift piston through said threaded opening.

5. In a semi-hydraulic lift including a cylinder, a hollow lift piston operatively associated with said cylinder, with the lift piston and the cylinder having a body of liquid therein, a liquid passage in the bottom of said lift piston open to said cylinder, means for introducing air under pressure into said lift piston above the level of the liquid therein means for controlling the flow of liquid through said passage including a tubular cylinder within said lift piston concentrically arranged about said liquid passage, a fioat piston within said tubular cylinder movable into and out of a passage closing position, an upright projection on said float piston, guide means extended upwardly from said tubular cylinder for guiding said float piston into and out of said tubular cylinder, said guide means having the top portion thereof extended upwardly and outwardly, an upright li uid level indicator in said lift piston having a guide portion at its lower end loosely receivable in a centered position within said guide means, with said projection being movably supported within said guide portion, a member for closing the upper end of said lift piston having an opening therein. a plug for closing said opening, and means for connecting said plug with the upper end of said indicator whereby said indicator is movable with said plug outwardly from said lift piston.

6. In a semi-hydraulic vehicle lift including a cylinder with a hollow cylindrical lift piston therein, with said cylinder and said lift piston containing a body of liquid, and the lift piston having a liquid passage adjacent its lower end for the flow of liquid between the lift piston and the cylinder, means within said lift piston for controlling the fiow of liquid through said passage including a float piston, an upright rod member in said lift piston for indicating the level of the liquid in the lift piston and the cylinder and adapted to be raised through an opening in the top of said piston, means for normally closing said opening connected with the upper end of said rod member, and a lost, motion connection between said float piston and the lower end of said rod memher to provide for said float piston being lifted through said opening with said rod member on removal of said rod member from said lift piston.

EIMER B. THOMPSON. 

